Year 5 Pathology > Micro > Flashcards

Micro Flashcards

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1
Q

Main pathogens that cause SSIs

A

Surgical site infections:
Staphlococcus aureus (MSSA and MRSA)
Escherichia coli
Pseudomonas aeruginosa

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2
Q

Pathology and types of SSIs

A

Wound contamination

  • superficial incisional (skin and subcut. tissue)
  • deep incisional (fascial and muscle)
  • organ/space infection (any part of anatomy other than incision)
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3
Q

Mx of SSIs

A

Ix
- clinical + wound swabs

Tx
- abx; flucloxacillin for Staph

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4
Q

Main pathogens that cause septic arthritis

A

Staphylococcus aureus

Streptococci
- pyogenes, pneumonia, agalactiae

Gram-negative
- Escherichia coli

Bacterial proliferation occurs in synovial fluid -> inflammatory response

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5
Q

Mx of septic arthritis

A

Ix

  • joint aspirate, MC&S
  • synovial count >50,000 WBC/ml
  • blood culture

Tx

  • IV abx
  • drain joint
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6
Q

Risk factors for septic arthritis

A 
Rheumatoid arthritis
Osteoarthritis
Joint prosthesis
IVDU
Diabetes, CKD, CLD
Immunosuppression
Trauma
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7
Q

Main pathogen that causes osteomyelitis

A

Staphylococcus aureus

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8
Q

Mx of osteomyelitis

A

Ix

  • MRI (90% sensitive)
  • blood cultures
  • bone biopsy for culture/histology

Tx

  • IV abx, at least 6 weeks
  • 2nd line; debridement
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9
Q

What results in osteomyelitis?

A

Acute haematogenous spread of bacteria or exogenous spread (implantation during surgery)

Mainly localises into lumbar spine, can also localise in cervical spine causing back pain, fever, and neurological impairment

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10
Q

Main pathogen that causes prosthetic joint infection

A

Coagulase-negative staphylococci
Staphylococcus aureus
Escherichia coli

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11
Q

Mx of prosthetic joint infection

A

Ix

  • XR/CT/MRI shows ‘loosening’
  • joint aspirate; CAUTION can cause infection if not already

Tx

  • IV abx
  • remove prosthesis and revise replacement
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12
Q

How may chronic osteomyelitis present?

A

Pain
Brodie’s abscess (within long bones)
Sinus tract of recurring infection in soft tissue over bone

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13
Q

Which abx drug class inhibit cell wall synthesis?

A

Beta-lactams

  • penicillins
  • cephalosporins (1-3 gens)
  • carbapenems

Glycopeptides

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14
Q

Which abx drug class inhibit protein synthesis?

A

Aminoglycosides
Macrolides
Chloramphenicol
Oxazolidinones

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15
Q

Which abx drug class inhibits DNA synthesis?

A

Fluoroquinolones

Nitroimidazoles

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16
Q

Which abx drug class produces cell membrane toxins?

A

Polymyxin

Cyclic lipopetide

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17
Q

Which abx drug class inhibits RNA synthesis?

A

Rifamycin

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18
Q

Which abx drug class inhibits folate metabolism?

A

Sulfonamides

Diaminopyrimidines

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19
Q

Which abx are indicated for MRSA?

A

Glycopeptides

  • vancomycin
  • teicoplanin

Oxazolidinones
- linezolid

Cyclic lipopeptide
- daptomycin

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20
Q

Which abx are indicated against gram positive bacteria?

A

Beta-lactams
- amoxicillin

Macrolides
- erythromycin (penicillin allergy)

Oxazolidinones
- linezolid

Cyclic lipopeptide
- daptomycin

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21
Q

Which abx are indicated against gram negative bacteria?

A

3rd gen cephalosporin
- ceftriaxone

Carbapenems
- meropenem

Aminoglycosides (for sepsis)
- gentamicin

Fluoroquinolones
- ciprofloxacin

Polymyxin
- colistin

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22
Q

Which abx are indicated for the following conditions:

a) C. diff
b) Chlamydia
c) Atypical pneumonia
d) Bacterial conjunctivitis
e) Anaerobes/protozoa
f) PCP
g) UTI

A

a) Glycopeptides; vancomycin, teicoplanin
b) Tetracycline; doxycycline
c) Macrolide; erythromycin
d) Chloramphenicol eye drops
e) Nitroimidazoles; metronidazole
f) Sulfonamide; sulphamethoxazole
g) Diaminopyrimidine; trimethoprim

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23
Q

Which abx are indicated for VRE?

A

Vancomycin resistant enterococci

Oxazolidinones
- linezolid

Cyclic lipopeptide
- daptomycin

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24
Q

Name broad spectrum abx

A

Co-amoxiclav (amox + clavulanic acid)

Tazocin (piperacillin + tazobactam)

Ciprofloxacin

Meropenem

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25
Name narrow spectrum abx
Flucloxacillin Metronidazole Gentamicin
26
Name the four mechanisms of abx resistance, including an example for each
1. Bypasses abx-sensitive step in pathway, i.e. MRSA 2. Enzyme-mediated drug inactivation, i.e. beta-lactams 3. Impairment of accumulation of drug, i.e. tetracycline resistance 4. Modification of drug's target in microbe, i.e. quinolone resistance
27
Which abx is likely prescribed for a skin infection?
Flucloxacillin (unless allergic) against Staph. aureus
28
Which abx is likely prescribed for pharyngitis?
Benzylpenicillin against beta-haemolytic strep
29
Which abx is likely prescribed for community-acquired pneumonia?
Amoxicillin if mild co-amox + clarithromycin if severe
30
Which abx is likely prescribed for hospital-acquired pneumonia?
Co-amox + gent/tazocin
31
Which abx is likely prescribed for bacterial meningitis?
Ceftriazone against meningococcus/streptococcus Amox if listeria suspected (baby/old)
32
Which abx is likely prescribed for a UTI?
Community - Trimethoprim - Nitrofurantoin Nosocomial - Co-amox - Cephalexin
33
Which abx is likely prescribed for sepsis?
Severe - tazocin/cetriazone + metronidazole +/- gentamicin Neutropenic - tazocin + gentamicin
34
Which abx is likely prescribed for colitis?
Metronidazole against C. diff Vancomycin 2nd line
35
Presentation of TB
Fever, night swears, wt loss, malaise Cough, haemoptysis More likely in immunosuppressed pts
36
Ix for TB
CXR - upper lobe cavitation Sputum samples x3 - microscopy, bronchoalveolar lavage Tuberculin skin tests (Mantoux/Heaf) - show exposure IGRA (Elispot/Quantiferon) - show exposure NOT BCG
37
What is the gold-standard ix for TB?
Ziehl-Neelson stain for culture on Lowenstein-Jensen medium for 6 weeks -> acid fast bacilli seen
38
How may TB present in pts with immunosuppresion?
Subacute meningitis - headache, personality change, meningism, confusion, LP diagnosis Spinal (Pott's disease) - back pain, discitis, vertebral destruction, iliopsoas abscess Miliary TB - disseminated haematogenous spread Pericarditis, peritonitis, renal, testicular, liver TB the list goes on...
39
TB risk factors
``` Travel (South Asian/Eastern Europe) Recent migration HIV+ Homeless IVDU Close contacts ```
40
1st line TB tx
Rifampicin (6 months) Isoniazid (6 months) Pyrazinamide (2 months) Ethambutol (2 months) - take three/four for 2 months - continue R and I for further 4 months
41
2nd line TB tx
Injectables (amikacin, kanamycin) Quinolones Linezolid
42
TB prophylaxis tx
Isoniazid monotherapy
43
What type of vaccine is BCG?
Bacille-Calmette-Guerin - attenuated strain of M. bocis - contraindicated in immunosuppression (live vaccine)
44
Side effects of TB tx
``` Rifampicin = orange secretions, CYP450 inducer, raised transaminases Isoniazid = peripheral neuropathy, hepatotoxicity Pyrazinamide = hepatotoxic Ethambutol = optic neuritis ```
45
Name four mycobacterial diseases
Leprosy (M. Leprae) - skin pigmentation, nerve thickening, disability Mycobacterium Avium-Intracellulare complex - immunocompromised pts, disseminated infection ``` Mycobacterium Marinarum (fish tank granuloma) - aquarium owners, papules/plaques ``` ``` Mycobacterium ulcerans (Buruli ulcer) - tropics/Australia, painless nodules progress to ulcers, scarring and contractures ```
46
Risk factors for reactivation of TB
Immunosuppression Chronic alcohol excess Malnutrition Ageing
47
What classic lesions are seen in pulmonary TB?
Caseating granulomata found in lung parenchyma and mediastinal lymph nodes Commonly in upper lobes
48
What does the tuberculin skin test do?
Mantoux test - looks for previous exposure thus looks for latent TB - delayed-type hypersensitivity reaction - cross-reacts with BCG so can confuse interpretation
49
What do IGRAs do?
Interferon gamma release assays - detection of antigen specific IFN gamma production to measure how many activated T cells against specific TB antigens - no cross-reaction with BCG - does NOT distinguish between latent and active TB
50
Risk factors for infective endocarditis
``` Long-term lines (i.e. ITU) IVDU Poor dentition/dental abscess Prosthetic valve Rheumatic heart disease Immunosuppression ```
51
Which pathogens are seen in acute infective endocarditis?
Acute -> high-virulence bacteria: 1. Strep pyogenes (Group A Strep) 2. Staph aureus (most common in IVDU) 3. Coagulase-negative staphylococci (most common in prosthetic valve)
52
Which pathogens are seen in subacute infective endocarditis?
Subacute -> low-virulence bacteria: 1. Staph epidermidis 2. Strep viridans 3. HACEK (uncommon and don't grow on culture so consider if culture -ve) - Haemophilus, Acinetobacter, Cardiobacterium, Eikinella, Kingella
53
How can infective endocarditis be classified?
``` Acute = fulminant illness, pt very unwell Subacute = over weeks/months, pt less unwell, more signs O/E ```
54
How can infective endocarditis be diagnosed?
Duke's Criteria: You need 2 major OR 1 major + 3 minor OR 5 minor criteria Major - +ve blood culture growing typical organisms (>2x cultures >12hrs apart) - new regurgitant murmur or evidence of vegetation on ECHO Minor - Risk factor - Fever > 38oC - Embolic phenomena - Immune phenomena - +ve blood culture not meeting major criteria
55
What embolic phenomena may you see in infective endocarditis?
``` Janeway lesions Splinter haemorrhages Splenomegaly Septic abscesses in lungs/brains/spleen/kidney Microemboli ```
56
What immune phenomena may you see in infective endocarditis?
Roth spots Osler's nodes Haematuria due to glomerulonephritis
57
Signs and sx of infective endocarditis
Fever Anorexia, wt loss, malaise, fatigue, night sweats, SOB New heart murmur, changes day to day, often regurgitant Subacute will see embolic and immune phenomena
58
Which valves are involved in infective endocarditits?
Usually involves mitral and aortic valves R sided (tricuspid) is most common in IVDU
59
Tx for infective endocarditis
IV abx for ~6 weeks (local guidelines) - Acute = flucloxacillin - Subacute = benzylpenicillin + gentamycin - Prosthetic valve = vancomycin + gentamycin + rifampicin Surgical debridement sometimes considered
60
How can UTIs be classified?
Uncomplicated vs complicated - complicated = abnormal structure, men, catheters, pregnancy Lower vs upper/pyelonephritis
61
Common pathogens causing UTIs
E. coli (can adhere to fimbriae) Staph saphrophyticus (young women) Proteus, Klebsiella (abnormal urinary tracts) S aureus (haematogenous spread)
62
Presentation of UTI
Frequency, dysuria, abdo pain - elderly = non-specific, delirium falls - pyelonephritis = systemically unwell, fever + rigors, loin pain - urosepsis = sepsis due to UTI
63
Ix of UTI
Clinical dx if typical sx Urine dip = +ve nitrites (specific) & leukocytes (non-specific) Urine MCS = culture of >10^4 units/ml is diagnostic
64
Rx of UTI
Check local guidelines - lower UTI = nitrofurantoin, trimethoprim, cephalexin PO, 3d if uncomplicated, 7d if complicated/male - pyelonephritis = admit, IV co-amox + gent
65
What UTI would be -ve nitrite and +ve leucocyte on dipstick?
Non-coliform bacterium *nitrites produced by E. coli, suggestive of coliforms present in urine
66
Causes of sterile pyuria
``` Prior tx with abx Calculi Catheterisation Bladder neoplasm TB STI ```
67
Why can fungal infections be difficult to diagnose?
Slow growing | Can be masked by bacteria
68
Yeast vs Mould
Yeasts - single celled, reproduce by budding Mould - multicellular hyphae, grow by branching and extension
69
What are fungi?
Eukaryotic organisms with chitinous cell walls and ergosterol plasma membranes They take the form of yeasts or moulds
70
Which fungal infections are diagnosed by Wood's Lamp examination?
Superficial
71
How are deep seated fungal infections diagnosed?
Clinical details Lab results Imaging
72
Who is at risk of fatal fungal infections?
Immunocompromised, i.e. malignancy, HIV, burns patients
73
Name two yeast fungal infections
Candida | Cryptococcus
74
Name two mould fungal infections
Dermatophytes | Aspergillus
75
Tx of candida
Fluconazole for C. albicans | Amphotericin-B for invasive disease
76
Aspergillus presentation
Pneumonia (especially in immunocompromised)
77
Tx of aspergillus
Voriconazole/intraconazole | + ambisome
78
Cryptococcus presentation
Meningitis with insidious onset in HIV Associated with birds, particularly pigeons ew
79
Tx of cryptococcus
3/52 amphotericin B | +/- flucytosine
80
What might India Ink staining of CSF show?
Cryptococcus fungal infection
81
What is PCP?
Pneumocystic jirovecii - pneumonia - cough, SOB, desaturates when walking - associated with immunodeficiency, immunosuppressive drugs, severe protein malnutrition
82
What is the name for the following dermatophyte fungal infections affecting the following parts of the body? a) Foot b) Scalp c) Groin d) Abdomen
a) Tinea pedis b) Tinea capitis c) Tinea cruris d) Tinea corporis
83
Which dermatophytes cause the following fungal infections? a) Tinea pedis b) Tinea capitis c) Tinea cruris d) Pityriasis versicolor
a) Trichophyton rubrum b) Trichophyton rubrum, Tonsurans c) Trichophyton rubrum, E. floccosum d) Malassezia globosa/furfur
84
What do dermatophytes invade?
Dead keratin of skin, hair and nails
85
Name the antifungal drug classes available
``` Polyene Azole Terbinafine Flucytosine (pyrimidine analogue) Echinocandin ```
86
Which antifungals act against the cell membrane?
Polyene (integrity) Azole (synthesis) Terbinafine
87
Which antifungals act against DNA synthesis?
Flucytosine
88
Which antifungals act against the cell wall?
Echinocandin
89
Which antifungals are indicated for yeasts?
Polyene Azole Echinocandin
90
Which antifungals are indicated for moulds?
Terbinafine
91
When is amphotericin B used?
Cryptococcal meningitis | Invasive fungal infection
92
Presentation of STIs in men
``` Asx Urethral discharge Dysuria Scrotal pain/swelling Rash/sores Systemic sx ```
93
Presentation of STIs in women
``` Asx Vaginal discharge (+/- urethral, rectal) Ulceration painful/painless Itching/soreness 'lumps/growths' Abnormal bleeding (IMB, PCB) Abdo pain Dyspareunia Dysuria Systemic sx ```
94
Which STIs cause abnormal discharge?
``` Gonorrhoea Chlamydia Trichomonas Candida Bacterial Vaginosis ```
95
Which STIs cause ulceration?
``` Syphilis - painful HSV - painless LGV Chancroid Donovanosis ```
96
Which STIs cause rashes and lumps/growths?
Genital warts (HPV) Molluscum contagiosum Scabies Pubic lice
97
Diagnosis and tx of gonorrhoea
Urethral (95% sensitive)/ rectal (20% sensitive) smear Ceftriaxone IM - 250mg single dose
98
Complication of gonorrhoea during pregnancy
During vaginal delivery, baby develops opthalmia neonatorum (neonatal conjunctivitis) if left untreated
99
What may you see in complicated infections of gonorrhoea?
Men - prostatitis Women - PID (salpingitis) - ascending infection Pts with complement deficiencies - disseminated infection: sepsis, rash, arthritis
100
What would you see in an uncomplicated infection of gonorrhoea in a man?
Gonococcal urethritis - mucoid/mucopurulent discharge Post-gonococcal urethritis - occurs after - requires extra tetracycline to treat Rectal proctitis - seen in MSM
101
What would you see in an uncomplicated infection of gonorrhoea in a woman?
Mucopurulent cervicitis - erythema and oedema - urethra (vaginal leakage)
102
Obligate intracellular gram -ve diplococcus taken on urethral swab of man with mucopurulent discharge Which pathogen is this?
Neisseria gonorrhoeae
103
Obligate intracellular gram -ve pathogen that cannot be cultured on agar found on genital swabs Which pathogen is this?
Chlamydia trachomatis
104
How is chlamydia classified?
Serovars A, B, C: trachoma (infection of eyes causing blindness) Serovars D-K: genital chlamydia, opthalamia neonatorum
105
Diagnosis and tx of chlamydia
NAAT from genital swabs Azithromycin 1g stat OR Doxycycline 100mg BD for 7 days
106
Complications of chlamydia
PID: tubal factor infertility, ectopic pregnancy, chronic pelvic pain Epididymitis Reactive arthritis Adult conjunctivitis, ophthalmia neonatorum
107
Which STI is commonly asx?
Chlamydia trachomatis - 50% men - 80% women
108
What is LGV?
Lympho-granuloma venereum - lymphatic infection with chlamydia trachomatis - endemic in developing world and MSM in developed world
109
1st stage sx of LGV
``` 3-12 days Painless genital ulcer Proctitis Balanitis Cervicitis ```
110
2nd stage sx of LGV
2wks-6months Painful inguinal buboes Fever Malaise
111
Late stage sx of LGV
Inguinal lymphadenopathy Genital elephantiasis Genital and perianal ulcers/abscesses Frozen pelvis
112
Diagnosis and tx of LGV
NAAT, genotypic identification of L1/2/3 serovar Doxycycline 100mg BD for 3 weeks
113
Haemophilus ducreyi, chocolate agar on culture What is this and main sx of pt?
Chancroid (gram -ve coccobacillus) Multiple painful ulcers
114
Large beefy red ulces and donovon bodies on Giemsa stain What is this and its tx?
Donovanosis = granuloma inguinale (Klebsiella granulomatis, gram _ve bacillus) Azithromycin
115
Name enteric pathogens that can cause STIs via the oro-anal route
Shigella Salmonella Giardia (protozoan) Strongyloides
116
What causes trichomoniasis?
Flagellated protozoan - T. vaginalis
117
Sx of trichomoniasis
Men: usually asx, urethritis Women: discharge, strawberry cervix
118
Diagnosis and tx of trichomoniasis
Wet prep microscopy (flagellated organisms seen), PCR Metronidazole
119
What causes bacterial vaginosis?
Abnormal vaginal flora results in polymicrobial environment, reducing lactobacilli present NOT transmitted, associated with sex and hygiene practices (soaps)
120
Diagnosis and tx of BV
Microscopy of gram stain, raised pH, whiff test, clue cells Lifestyle (no soaps, only water washing) Metronidazole PO/topical
121
Diagnosis and tx of candidiasis
Clinical - thick white discharge, itching, redness Associated with immunodeficiency, hygiene practices PO/topical antifungals - clotrimazole - fluconazole
122
Name viral STIs
Hepatitis - HAV, HBV, HCV Herpes HIV
123
Which pathogen causes genital warts?
dsDNA Human Papillomavirus - HPV 6, 11 - NOT associated with cervical dysplasia
124
Diagnosis and tx of genital warts
Clinical - papular, planar, pedunculated, carpet, keratinised, pigmented lesions Home tx - podophyllotoxin solution/cream (NOT for pregnant women) Clinic tx - cryotherapy - imiquimod
125
Which pathogen causes syphilis?
Treponema pallidum
126
Describe treponema pallidum
Obligate gram -ve spirochaete
127
Primary syphilis
Macule -> papule -> painless solitary genital ulcer Appears 1-12 weeks after transmission Can persist 4-6 weeks (chancre) Regional adenopathy
128
Secondary syphilis
Systemic bacteraemia 1-6 months after infection Rash on palsm and soles Condyloma acuminate (genital warts_ Mucosal lesions, uveitis Neurological involvement
129
Tertiary syphilis
2-30 years later, 3 syndromes: 1. Gummatous - skin/bone/mucosa granulomas - spirochaetes scanty 2. Cardiovascular - aortic root dilatation/aortitis - spirochaetes +++, inflammation +++ 3. Neurosyphilis - dementia, tabes dorsalis, Argyll-Robertson pupil - spirochaetes in CSF
130
Diagnosis of syphilis
Treponemes seen in primary lesions by dark-ground microscopy Antibody tests 1. Non-treponemal = VDLR slide test, non-specific, useful in primary syphilis 2. Treponemal = detects Abs against specific antigens, EIA/FTA/TPHA, remains +ve for years after tx
131
Tx of syphilis
Single dose IM benzathine penicillin - doxycycline if allergic - monitor RPR for x4-fold reduction
132
Side effect of syphilis tx
Jarisch-Herxheimer reaction - flu-like sx, exacerbation of syphilitic sx - develops within hours of taking abx - clears within 24hrs
133
Causes of immunocompromise
Transplant AIDS Iatrogenic: chemotherapy/biologics Rare genetic causes
134
Which viruses cause more severe disease in the immunocompromised?
Herpesviridae - CMV, EBV, HSV, HHV8, VZV Polyomaviridae - JC virus, BK virus Respiratory - influenza A & B, parainfluenza 1-6, RSV, adenovarius, MERS cornavirus
135
Which fungi cause more severe disease in the immunocompromised?
``` Candida Cryptococci Aspergillu Dermatophytes Mucormycosi ```
136
Which organism can cause all of the following syndromes? Catheter associated BSI Urinary catheter associated UTI Surgical site infection
MRSA
137
Which organism can cause all of the following syndromes? Antibiotic associated diarrhoea
C. difficile
138
Which organism can cause all of the following syndromes? Urinary catheter associated UTI Ventilator associated pneumonia
E. coli
139
Which organism can cause all of the following syndromes? Catheter associated BSI Surgical site infection
MSSA
140
Which organisms can cause all of the following syndromes? Catheter associated BSI Urinary catheter associated UTI Surgical site infection Ventilator associated pneumonia
Gram negatives
141
Which organisms can cause all of the following syndromes? Catheter associated BSI Urinary catheter associated UTI
Yeasts/candida
142
Most common syndromes of HAI
Hospital-acquired pneumonia Surgical site infections Urinary tract infections
143
Predisposing factors for C. diff
Existing gut flora disturbed by abx, particularly by 3 Cs: - clindamycin - cephalosporins - ciprofloxacin
144
When is clindamycin typically used?
Given to pts with penicillin allergy when they have cellulitis
145
Why does C. diff result in diarrhoea?
Toxins produced after spore ingestion Leads to pseudomembranous colitis
146
Rx for C. diff
Oral metronidazole
147
What are the three fibrous membranes that protect the CNS?
Pia mater Arachnoid mater Dura mater
148
20yo woman presents with headache and neck stiffness Gram +ve diplococci Blood agar show alpha haemolysis Dx?
Streptococcus pneumoniea meningitis - gram+ve alpha-haemolytic diplococcus
149
18 yo man presents with headache and neck stiffness CSF shows loads of neutrophils Gram -ve diplococci with no haemolysis Dx?
Meningococcus | - Neisseria meningitidis
150
65 yo woman presents with headache and neck stiffness Gram +ve rods Dx?
Listeria monocytogenes
151
45 yo presents with chronic headache and neck stiffness Ziehl-Neelsen stain is red and blue Dx?
TB meningitis
152
Bacterial causes of meningitis
Neisseria meningitidis (gram -ve) Streptococcus pneumoniea (gram +ve) Haemophilus influenzae Group B strep (elderly/neonates/immunocompromised) Listeria monocytogenes (elderly/neonates/immunocompromised) E. coli (neonates)
153
Viral causes of meningitis
Enterovirus (coxsackie, echovirus) Mumps HSV2
154
Fungal cause of meningitis
Cryptococcus neoformans (chronic)
155
Meningitis that presents with headaches for months
TB | Cryptococcus
156
Encephalitis summary
Inflammation of brain parenchyma Sx: confusion, fluctuating consciousness Commonly viral (HSV1) Rx: IV acyclovir
157
Brain abscess summary
Localised collection of infection Sx: SOL, swinging fever Commonly due to local extension (otitis media) or haematogenous spread (endocarditis)
158
Organisms that cause bacteraemia
MRSA Coag -ve staph E. coli
159
Risk factors for bacterial meningitis
Overcrowding Very young/very old N. meningitidis: - complement deficiency - hyposplenism - hypogammaglobulinaemia S. pneumoniea: - complement deficiency - hyposplenism - immunosuppressed (alcoholic) - infection (pneumonia) - entry # - previous head trauma w/ CSF leak
160
Rx for bacterial meningitis
Resuscitate! IV ceftriaxone and corticosteroids Cover Listeria with ampicillin
161
Appearance: turbid Glucose: low White cells: high Cell type: polymorphs Dx?
Bacterial meningitis
162
Appearance: clear Glucose: normal White cells: high Cell type: mononuclear Dx?
Viral meningitis
163
Appearance: turbid Glucose: normal White cells: high Cell type: polymorphs Dx?
Partially treated bacterial meningitis
164
Appearance: clear/turbid Glucose: low White cells: high Cell type: mononuclear, protein present Dx?
TB meningitis
165
Describe viruses from the family Orthomyxoviridae
Enveloped virus Wild-type virion, filamentous morphology Negative sense segmented RNA genome (8 segments)
166
Which 3 antigenically different flus affect humans and during which period of the year?
``` Influenza A (H1) = peaks beginning January Influenza A (H1N1) = peaks end December Influenza B = peaks March ```
167
Define antigenic drift
Accumulation of point mutations changing the nature of the antigen over time (drift)
168
Define antigenic shift
Recombination of genomic segments during assembly and egress of two co-infecting flu strains Leads to rapid potentially whole antigenic change for a viral strain (shift)
169
Antivirals for influenza
Amantadine (Influenza A) Neuraminidase inhibitors - oseltamivir (tamiflu) - zanamivir (relenza) - sialic acid
170
Neuraminidase (sialidase) activity in viral RNA segments action
Cleaves sialic acid residues, allowing exit of virions from host cells, disrupting mucin barrier
171
TORCH infections
``` Toxoplasmosis Other (HIV, Hep B, syphilis) Rubella CMV HSV ```
172
Presentation of congenital infection
``` Thrombocytopenia Other (eyes/ears - cataracts, chorioretinitis) Rash Cerebral abnormality, i.e. microcephaly Hepatosplenomegaly ```
173
Early onset vs late onset neonatal sepsis defintion
Early onset = < 48 hours after birth | Late onset = > 48 hours after birth
174
Early onset neonatal sepsis causative agents
Group B streptococci E. coli Listeria
175
Late onset neonatal sepsis causative agents
Coagulase -ve staph + GBS E. coli Listeria
176
Abx tx in early onset neonatal sepsis
BenPen + gentamicin | Amox/ampicillin if Listeria
177
Abx tx in late onset neonatal sepsis
1st line = benzylpenicillin + gentamicin 2nd line = tazoxin + vancomycin Community = amox + cefotaxime (BenPen given in GP)
178
Ddx in fever in a returning traveller
``` Malaria Typhoid Dengue Viral haemorrhagic fever Bacterial diarrhoea (E. coli, cholera) ```
179
Typhoid pathogens
Salmonella typhi and paratyphi
180
Anaerobic gram -ve bacilli in pt returning from India with fever
Salmonella typhi | - causes enteric fever
181
Fever, constipation, rose spots in pt returning from India What rx needed?
Typhoid! IV ceftriaxone then PO azithromycin
182
Dengue pathogen
Flavivirus spread by Ades mosquito
183
Pt comes back from Thailand with fever, myalgia, and rash Top ddx?
Dengue | - consider dengue haemorrhagic fever/dengue shock syndrome if re-infected
184
Malaria pathogen
Plasmodium spp. (protozoal infection) spread by female Anopheles mosquito
185
Features of severe falciparum malaria
``` Impaired consciousness/seziures Renal impairment Acidosis Hypoglycaemia Anaemia Spontaneous bleeding/DIC Shock Haemoglobinuria (without G6PDD) ```
186
Non-falciparum malaria species
Plasmodium - vivax - ovale - malariae - knowlesi Less severe, Schuffners dots on blood film
187
Tx of falciparum malaria
Mild - artemesin combination therapy (Riamet - aremether + lumefantrine) Severe - IV artesunate (1st line - quinolone if 1st line not available)
188
Tx of non-falciparum malaria
Chloroquine then primaquine
189
Postive ix for falciparum malaria
THREE Thick and thin blood films - thick = identify malaria - thin = identify species Field's or Giemsa stain
190
Which pathogens should you consider in the UK from the following types of animals? a) Farm/wild b) Companion
a) Campylobacter, Salmonella | b) Bartonella, Toxoplasmosis, Ringworm, Psittacosis
191
Which pathogens should you consider in tropical areas/outside the UK from the following types of animals? a) Farm/wild b) Companion
a) Brucella, Coxiella, Rabies, VHF | b) Rabies, Tick-borne diseases, Spirillum minus
192
Farmer comes in with fever worse in the evenings, arthritis, and hepatosplenomegaly Cultures show gram -ve aerobic bacilli What is ddx?
Brucellosis - contaminated milk/dairy products - direct contact w cows, goats, sheep, pigs
193
Farmer comes in with fever worse in the evenings, arthritis, and hepatosplenomegaly Cultures show gram -ve aerobic bacilli What is tx?
Brucellosis | - 4-6 weeks doxycycline + streptomycin
194
Negri bodies on serology in pt presenting with fever, sore throat, and headache Diagnosis?
Rabies - eosinophilic, sharply outlined, pathognomonic inclusion bodies found in the cytoplasm of certain nerve cells containing the virus of rabies, especially in pyramidal cells within Ammon's horn of the hippocampus
195
Plague pathogen
Yersinia pestis - gram-ve lactose fermenter - still in American National Parks, i.e. Yosemite
196
Pt presents with high fever, red conjunctiva, and jaundice They recently went on holiday and swam in a still body of water in an area full of stray dogs and a rat problem Most likely pathogen?
Leptospirosis interrogans - gram -ve - obligate, aerobic, motile spirochaetes
197
Compare cutaeneous and pulmonary presentations of anthrax
Cutaneous - painless round black lesions + rim of oedema Pulmonary - massive lymphadenopathy + mediastinal haemorrhage
198
Lyme disease pathogen
Borrelia burgdoferi (spirochaete) - Arthropod-borne - Ixodes = tick
199
Pt presents with expanding ring of redness on their leg after a hike in Richmond Park, and flu-like sx Which tx do they need?
Lyme disease - erythema chronicum migrans (bullseye rash) Doxycycline 2-3 weeks (also amox, cephalosporins) - CNS issues, IV cef 2-4 weeks
200
Vet presents with a dry cough, high fever, aching muscles No rashes on O/E and does not respond to initial abx tx for CAP Potential pathogen and next abx px?
Q fever - Coxiella burnetii Doxycycline
201
Rat Bite fever pathogens
Streptobacillus moniliformis (USA) Spirillum minus (Asia/Africa) *from rat bites, contact with infected urine or droppings
202
Which protozoa pathogen cause the following types of Leishmania? a) Cutaneous b) Diffuse cutaneous c) Muco-cutaneous d) Visceral
a) L. major, L tropica b) " " c) L. braziliensis d) L. donovani, L. infantum, L. chagasi in S. America
203
CAP organisms
``` Streptococcus pneumoniae Haemophilus influenzae Moraxella catarrhalis Staphylococcus aureus Klebsiella pneumoniae ```
204
Main causes of cavitation on CXR
Staphylococcus aureus Klebsiella pneumoniae TB
205
Atypical pneumonia causes
``` Legionella pneumophilia Mycoplasma pneumoniae Chlamydia pneumoniae Chlamydia psittaci Coxiella burnetii ```
206
Which pneumonia has extra-pulmonary features? Include what they are
Atypical pneumonia - hepatitis - hyponatraemia
207
Cough, fever, rusty-coloured sputum | Micro: +ve diplococci
Streptococcus pneumoniae
208
Cough, fever, smoker with COPD background | Micro: -ve cocco-bacilli
Haemophilus influenzae
209
Cough, fever, smoker | Micro: -ve cocci
Moraxella catarrhalis
210
Post-influenza cough, fever | Micro: +ve cocci "grape-bunch clusters"
Staphylococcus aureus
211
Cough, fever, haemoptysis, alcoholic | Micro: -ve rod, enterobacter
Klebsiella pneumoniae
212
Travel, air conditioning, water towers pneumonia pathogen
Legionella pneumophilia
213
Uni students, dry cough, arthralgia with autoimmune haemolytic anaemia and erythema multiforme pneumonia pathogen
Mycoplasma pneumoniae
214
Pathogens seen in HIV pts
Pneumocystis jiroveci TB Cryptococcus neogormans
215
Pathogens seen in splenectomy pts
Encapsulated organisms - Haemophilus influenzae - Streptococcus pneumoniae - Neisseria meningitis
216
Pathogens seen in CF pts
Pseudomonas aeruginosa | Burkholderia cepacia
217
Pathogens seen in neutropenia pts
Aspergillus
218
Tx of mild pneumonia
CURB 0-1 = Amoxicillin PO 5d = 2nd line/pen allergy: macrolide PO 5d = outpatient
219
Tx of moderate pneumonia
CURB 2 = Amoxicillin PO 5-7d + clarithromycin PO 5-7d = consider admission
220
Tx of severe pneumonia
CURB 3-5 = Co-amoxiclav IV 7d + clarithromycin IV 7d = Admit +/- consider ITU
221
CURB 65 scoring
1 point for: - Confusion - Urea - RR > 30 - BP < 90/60 - >/= 65
222
Tx of HAP
Depends on trust guidelines, generally: 1st line - ciprofloxacin + vancomycin Severe - tazocin + vancomycin Aspiration - tazocin + metronidazole
223
What do raised marker 14-3-3 protein S100 represent?
Rapid neurodegeneration
224
Where is the prion protein gene?
Chr 20, predominately expressed in CNS
225
CJD tx
Symptomatic - clonazepam for myoclonus - valproate, levetiracetam, piracetam Delaying prion 'conversion' - quinacrine, pentosan, tetracycline
226
Genetic mutations seen in CJD
Codon 129 polymorphism | Specific PRNP mutations
227
Rapid, progressive dementia with myoclonus, cortical blindness, akinetic mutsim and lower motor neuron signs What is this condition and its typical onset and prognosis?
Sporadic CJD (80% cases) Mean onset 45-75 yrs and mean survival time within 6/12 of sx starting
228
Anxiety, paranoia, hallucinations followed by development of peripheral sensory sx, ataxia, and myoclonus What is this condition and its typical onset and prognosis?
Acquired variant CJD Younger age of onset, typically < 30 yrs Later sx: choreo, ataxia, dementia (not great)
229
Presents with progressive ataxia after a surgery that leads onto dementia and myoclonus later on What is this condition and its aetiology?
Acquired iatrogenic CJD Inoculation with human prions - from surgery - from transfusions
230
Progressive cerebellar syndrome with dementia sx at end stage of disease What is this condition and its prognosis?
Acquired kuru CJD - result of exposure to human prions via cannibalism following 45 yr incubation Death within 2 years
231
Dysarthria starts around 30 years old and progresses to cerebellar ataxia ending ini dementia What is this condition and how is it passed on?
Gerstmann-Straussler-Scheinker syndrome (inherited prion disease) - familail CJD, GSS, FFI, atypical dementia Autosomal dominant 20-60 yr onset, mean survival = 5 yrs
232
Insomnia and paranoia progresses to hallucinations and weight loss. Pt is then mute and dies after 6 months of sx onset What is this condition and how is it passed on?
Fatal Familial Insomnia (inherited prion disease) - PRNP mutations Autosomal dominant Death 1-18/12 after sx onset
233
Secretory diarrhoea clinical syndrome
Toxin production => Cl- secreted into lumen => loss of water and electrolytes => D&V Watery diarrhoea, no fever
234
Inflammatory diarrhoea clinical syndrome
Inflammation and bacteraemia Bloody diarrhoea (dysentry) and fever
235
Enteric fever clinical syndrome
Unwell with fever, fewer GI symptoms
236
Student eats canned packed beans and later has D&V followed by descending paralysis Which organism is this?
Clostridium botulinum | - antitoxin is tx
237
Reheated meat consumed and 8 hours later patient has watery diarrhoea and cramps lasting for an entire day but presents to A&E due to blackening of right leg and extreme pain Which organism is this?
Clostridium perfringens | - gas gangrene!! emergency!!
238
Which abx cause pseudomembranous colitis?
Cephalosporins Ciprofloxacin Clindamycin Co-amoxiclav
239
C diff tx
1st: metronidazole 2nd: vancomycin
240
Sudden D&V, no blood in stool and instead very watery. Patient noted to have had chinese takeout last night. Which organism is this?
Bacillus cereus - self-limiting - reheated rice, short incubation round 4 hours
241
Prominent vomiting and watery diarrhoea. Stool cultures show gram +ve clusters of cocci Which organism is this?
Staph aureus
242
What do the following types of E. coli syndromes cause? a) ETEC b) EIEC c) EHEC d) HUS e) EPEC
a) toxigenic - traveller's diarrhoea b) invasive dysentery c) haemorrhagic d) anaemia, thrombocytopenia, renal failure (0157:H7 toxin) e) infantile diarrhoea (Paeds)
243
Fever, constipation and rose spots noted. What is organism and tx?
Salmonella typhi/paratyphi IV ceftriaxone then PO azithromycin
244
Uncooked meat and eggs eaten at BBQ, leading to non-bloody diarrhoea Which organism is this?
Salmonella enteritides
245
What does shigella affect?
Distal ileum and colon - > mucosal inflammation - > fever, pain - > bloody diarrhoea
246
Rice water stool, what is the shape of the organism?
Vibrio cholera | - comma shaped bacteria
247
Organism common in Japan that can cause D&V after consumption of raw seafood
Vibrio parahaemolyticus
248
Organism that causes cellulitis in shellfish handlers
Vibrio vulnificus
249
Chicken at BBQ eaten then patient felt a bit unwell, eventually followed by abdo cramps and bloody diarrhoea Which organism is this?
Campylobacter jejuni | - lasts around 10 days
250
Complications of campylobacter infection
GBS | Reactive arthritis
251
Campylobacter tx
Erythromycin or cipro if in first 5 days
252
Elderly man on long-term steroids eats unpasteurised dairy and presents with nasty D&V Which organism is this?
Listeria monocytogenes | - severe infection in immunocompromised, pregnant, neonates
253
Listeria tx
Ampicillin
254
Patient presents with dysentery, flatulence, and tenesmus Flask-shaped ulcer on histology of colon Which organism is this?
Entamoeba histolytica | - more common in MSM
255
Patient presents with foul-smelling non-bloody diarrhoea. Recent history of hiking for the past week Pear-shaped trophozoite on histology Which organism is this?
Giardia lamblia | - affect travellers, hikers, residential homes, psych inpatients, MSM
256
Entamoeba histolytica tx
Metronidazole
257
Giardia tx
Metronidazole
258
Severe diarrhoea in immunocompromised caused by a protozoa
Cryptosporidium parvum | - tx: paromomycin
259
What viruses cause D&V?
``` Norovirus - adults Adenovirus - < 2 years old Rotavirus - < 6 years old ``` *all cause secretory diarrhoea
260
HSV tx
1st line: Acyclovir 2nd line: Valaciclovir PO first, IV severe
261
VZV tx
Acyclovir 800mg PO TDS 7/7 or Valaciclovir 1g TDS or VZIG post-exposure for immunocompromised/pregnant women
262
VZV congenital infection
Eyes: chorioretinitis, cataracts Neurological: microcephaly, cortical atrophy MSK/skin: limb hypoplasia, cutaneous scarring
263
VZV neonate infection
Purpura fulminans Visceral infection Pneumonitis
264
Shingles tx
``` Aciclovir 800mg PO x5 daily Famciclovir 250mg PO TDS Valaciclovir 1g PO TDS Topical eye drops PEP 7-9/7 for immunocompromised ```
265
CMV congenital infection
``` Ears: sensorineural deafness Eyes: chorioretinitis Heart: myocarditis Neurology: microcephaly, encephalitis Lung: pneumonitis Liver: hepatitis, jaundice, hepatosplenomegaly ```
266
CMV tx
1st line = ganciclovir IV = valganciclovir PO 2nd line = foscarnet IV (nephrotoxic) 3rd line = cidofovir IV IVIg if pneumonitis present
267
Which abx should you avoid in EBV infection?
Penicillin | = provoke widespread maculopapular rash known as infectious mononucleosis exanthema
268
Which virus causes Kaposi's sarcoma?
HHV8
269
Name two polyomaviridae viruses
JC virus BK virus Occurs in immunocompromised patients!
270
JC virus features and tx
Progressive multifocal leukoencephalopathy Rapidly demyelinating disease with neurological deficits Tx: Anti-retrovirals
271
BK virus features and tx
BK haemorrhagic cystitis BK nephropathy Tx: Cidofovir
272
Influenza tx
Oseltamivir (tamiflu)
273
Adenovirus tx if multiorgan involvement
Cidofovir, IVIG
274
Hep B drug tx
1. Interferon alpha 2. Lamivudine 3. Entecavir 4. Telbivudine 5. Tenofovir 2-5 = nucleoside analogues
275
Hep C drug tx
Initially interferon therapy (Peg INF-alpha 2b/2a) Then direct acting antivirals: 1. NS3/4 protease inhibitors (-previrs; block translation) 2. NS5A inihbitors (-asvirs; block release) 3. Direct polymerase inhibitors (-buvirs; block replication)
276
Hep D drug tx
Peginterferon-alpha
277
Congenital rubella syndrome
Ears: sensorineural deafness Eyes: cataracts, glaucoma, retinopathy, microphthalmia Heart: PDA, VSD Neurology: microcephaly, psychomotor retardation Pancreas: insulin dependent DM (late)
278
Parovirus B19 congenital infection
Foetal anaemia Cardiac failure Hydrops foetalis
279
What does morbillivirus cause?
Measles!!
280
Congenital zika infection
``` Severe microcephaly & skull deformity Decreased brain tissue, subcortical calcification Retinopathy, deafness Talipes, contractures Hypertonia ```
281
1. Anti-HAV IgM 2. Anti-HAV IgG What would you expect to see for Hep A in the following? a) acute infection b) previous infection c) vaccinated
1. Anti-HAV IgM 2. Anti-HAV IgG a) 1. + 2. - b) 1. - 2. + c) 1. - 2. +
282
1. Anti-HEV IgM 2. Anti-HEV IgG What would you expect to see for Hep E in the following? a) acute infection b) previous infection c) vaccinated
1. Anti-HAV IgM 2. Anti-HAV IgG a) 1. + 2. - b) 1. - 2. + c) Not yet widely available, tricked u bb
283
1. Anti-HCV IgG 2. HCV RNA What would you expect to see for Hep C in the following? a) acute infection b) previous infection c) chronic infection
1. Anti-HCV IgG* 2. HCV RNA a) 1. - 2. + b) 1. + 2. - c) 1. + 2. + * note: utility still widely contested, not commonly used
284
1. HBsAg 2. Anti-HBc (core antigen) 3. IgM anti-HBc 4. Anti-HBs (surface antigen) What would you expect to see for Hep B in the following? a) acute infection b) chronic infection c) previous infection d) vaccinated
1. HBsAg 2. Anti-HBc 3. IgM anti-HBc 4. Anti-HBs a) 1. + 2. + 3. - 4. - b) 1. + 2. + 3. + 4. - c) 1. + 2. - 3. - 4. - d) 1. - 2. - 3. + 4. +
Year 5 Pathology
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